An ethics watchdog group has filed a complaint over President Donald Trump's pick to head the Department of Homeland Security for hiring the co-founder of a lobbying firm to help guide her through the confirmation process.

Kirstjen Nielsen hired former lobbyist Thad Bingel, co-founder of the Command Group, to help shepherd her through the confirmation procedure. The Campaign Legal Center issued a complaint Monday to White House chief of staff John Kelly, who Nielsen currently serves under as his deputy, U.S. Attorney General Jeff Sessions, and Office of Government Ethics acting Director David Apol.

"It appears that Nielsen has been guided through the confirmation process by an individual whose clients have hundreds of millions in contracts before the agency she has been nominated to lead," CLC wrote in the complaint, referring to Command Group's. "This implicates several potential violations of federal laws and regulations. It also offends common sense notions of the meaning of conflicts of interest."

CLC general counsel Larry Noble told The Washington Post on Thursday that Bingel "has clear financial incentive to assist in the nomination of an agency secretary who would have the power to steer government contracts in his direction."

"Government employees aren't permitted to receive gifts or free services — especially from people with business before their department — because it calls the integrity of government decision-making into question," he added. "This unusual arrangement should be investigated because of the clear potential conflict of interest, and the danger that Nielsen can be compromised as DHS secretary."

President Donald Trump's pick to head the Department of Homeland Security has hired the co-founder of a lobbying firm to help guide her through the confirmation process, leading an ethics watchdog group to file a complaint.